1.1. Crotonic acid, C₄H₆O₂, is used in the manufacture of paints and adhesives.

State the empirical formula of crotonic acid.

1.2. The systematic name of crotonic acid is but-2-enoic acid.

Draw two displayed formulae for possible isomers of crotonic acid that retain the carboxylic acid functional group.

1.3. Oleic acid is a fatty acid which occurs naturally in different animals and plants. The structure of oleic acid is shown in Fig. 2.1.

Fig. 2.1

i) Identify the type of formula shown in Fig. 2.1. 

[1]

ii) Deduce the molecular formula of oleic acid. 

[1]

iii) Explain whether oleic acid belongs to the same homologous series as crotonic acid.

[3]